Electronic devices having electronic components and electronic materials in recent years are used under various environments due to expansion of their use. For example, use of an electronic device under a highly humid environment may cause condensation in the electronic device. Due to this condensation, conductors may be shortcircuited, consequently leading to breakdown of the electronic device. For this reason, there has been an increasing demand for a suitably evaluation of the durability (electric insulation) of electronic devices against condensation.
For example, Patent Documents 1 and 2 each discloses an apparatus for conducting a condensation test. In the apparatus described in Patent Document 1, a seat for placing thereon a test piece is cooled to keep the temperature of the seat constant at a temperature nearby the dew-point temperature of the test chamber. This way, the apparatus maintains the condensation status of the test piece for a long time.
Further, in the apparatus of Patent Document 2, a condensation amount is determined based on an image of the surface of a test object taken by a TV imaging device, and a signal relative to the condensation amount is input to a cooler control unit. Then, the test object is cooled by a cooler to achieve a set condensation amount by the surface of the test object. Note that cooling of the test object is controlled by using the maximum cooling capability of the cooler.